1. Field of the Invention
The present invention relates to apparatus and methods for use in coordinating the operation of heating, ventilation, and air conditioning (HVAC) units in variable air volume (VAV) systems.
2. Prior Art
The present invention relates to microcomputer based control systems used in variable air volume (VAV) systems. Typically, large HVAC units supply conditioned air to the various zones which may or may not have individual zone dampers. As various zone dampers modulate closed because the zone demands have been met, as established by a local thermostat, the air flow through the remaining dampers will increase. Methods of accommodating the additional and often excessive air flow; that can result consist generally of air control systems such as discharge dampers and variable speed fans as explained in the copending application "Fan-Powered Mixing Box Assembly", these difficulties and others can be overcome by treating each of several large fan-powered mixing box assemblies as though it were a separate HVAC unit operated by a microcomputer-controlled monitor with zone dampers controlled via VVT monitorstats as described in the related U.S. Applications identified above. However, central HVAC units are still required because the fanpowered mixing box assemblies have no independent source of cooling and the economics of scale argue in favor of central heating sources.
The present invention discloses a microcomputer-controlled VAV system coordinator (VSC) which can be configured to operate as three different application specific types of VSCs: (1) as a VSC used as part of an electronic VAV system to coordinate the central system VAV cooling and heating operation based on the zone requirements of its associated slave thermostats and fan box monitors; (2) as a slave VSC as part of an electronic VAV system to communicate and store information from its associated slave thermostats and fan box monitors and supply the information to the associated master VSC for overall system coordination; and (3) as a master VSC coordinating central heating and cooling based upon zone information received from its associated slave VSCs.
The present invention provides base of operation and maintenance and a degree of zone control and system coordination for superior to prior art VAV systems employing fan-powered mixing boxes.